The use of integrated service, digital network (i.e., ISDN) lines in telephone communications has become increasing popular. For example, U.S. Pat. No. 5,305,312 for an Apparatus For Interfacing Analog Telephones And Digital Data Terminals to an ISDN Line to Fornek et al. discloses an ISDN interface for up to two analog dual tone multi-frequency telephones and for up to four personal computers or data terminals. ISDN line comprises D channel and two B channels for multiplexing. Also, U.S. Pat. No. 5,204,860 for a Network Terminating Terminal Apparatus For Integrated Services Digital Network to Sparks discloses a network terminator terminal apparatus for use in an ISDN system. A telephone handset as well as a computer terminal communicate via ISDN communication with an outside exchange. Channel 2B+D transmit and receive signals are used in the communication. Next, U.S. Pat. No. 5,276,687 for a Network System Having Different Attributes Of Terminal Equipment Devices to Miyamoto discloses a terminator network that connects a facsimile machine, computers, telephones to an outside transmission line. D channels and B channels are used to communicate between the outside transmission line and the various equipment attached to the network terminator. As a result, numerous electronic communications equipment can use a single telephone access line simultaneously using an ISDN form of communication and a network terminator. Finally, U.S. Pat. No. 5,481,605 for a Private Branch Exchange Capable of Analyzing Information Received From ISDN to Sakurai et al. discloses a private branch exchange capable of using information received in ISDN form. B channels and D channels are used to communicate with various communications equipment including telephones, facsimile machines, and so forth.
I have discovered a need for a simple ISDN circuit that accommodates just one telephone and one computer terminal. Both the telephone and the computer terminal share access to a single telephone line originating from a central office via time multiplexing.